Electric power grids are increasingly connected to the Internet. As a result, electric power grids may be vulnerable to threats, such as cyber-attacks (e.g., associated with a computer virus, malicious software, etc.), that could disrupt electric power generation and distribution, damage equipment, etc. Current methods of protection from this type of harm primarily consider threat detection in Information Technology (“IT,” such as, computers that store, retrieve, transmit, manipulate data) and Operation Technology (“OT,” such as direct monitoring devices and communication bus interfaces). Cyber-threats can still penetrate through these protection layers and reach the physical “domain.” Such attacks can diminish the performance of an electric power grid and may cause a total shut down or even catastrophic damage. Currently, Fault Detection Isolation and Accommodation (“FDIA”) approaches only analyze sensor data, but a threat might occur in connection with other types of data source nodes. Also note that FDIA is limited only to naturally occurring faults in one sensor at a time. FDIA systems do not address multiple simultaneously occurring faults as they are normally due to malicious intent. It would therefore be desirable to protect an electric power grid from malicious intent such as cyber-attacks in an automatic and accurate manner.